XML 33 R50.htm IDEA: XBRL DOCUMENT v2.4.0.6
Borrowings and Other Financing Instruments (Details) (USD $)
 3 Months Ended 12 Months Ended 12 Months Ended 1 Months Ended 12 Months Ended 1 Months Ended 12 Months Ended 1 Months Ended 12 Months Ended 12 Months Ended 1 Months Ended 12 Months Ended
Dec. 31, 2011
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Oct. 31, 2011
Dec. 31, 2011
Preferred Stock [Member]
Dec. 31, 2010
Preferred Stock [Member]
Dec. 31, 2011
Common Stock [Member]
Dec. 31, 2010
Common Stock [Member]
Dec. 31, 2011
NSP-Minnesota [Member]
Dec. 31, 2010
NSP-Minnesota [Member]
Aug. 31, 2010
NSP-Minnesota [Member]
First Mortgage Bonds, Series Due Aug. 15, 2015 [Member]
Aug. 31, 2010
NSP-Minnesota [Member]
First Mortgage Bonds, Series Due Aug. 15, 2040 [Member]
Dec. 31, 2011
PSCo [Member]
Dec. 31, 2010
PSCo [Member]
Dec. 31, 2011
PSCo [Member]
Preferred Stock [Member]
Aug. 31, 2011
PSCo [Member]
First Mortgage Bonds, Series Due Aug. 15, 2041 [Member]
Nov. 30, 2010
PSCo [Member]
First Mortgage Bonds, Series Due Nov. 15, 2020 [Member]
Dec. 31, 2011
SPS [Member]
Dec. 31, 2010
SPS [Member]
Dec. 31, 2011
SPS [Member]
Preferred Stock [Member]
Aug. 31, 2011
SPS [Member]
First Mortgage Bonds, Series Due Aug. 15, 2041 [Member]
Dec. 31, 2011
NSP-Wisconsin [Member]
Dec. 31, 2010
NSP-Wisconsin [Member]
Dec. 31, 2011
Xcel Energy Inc. [Member]
Dec. 31, 2010
Xcel Energy Inc. [Member]
Dec. 31, 2009
Xcel Energy Inc. [Member]
Sep. 30, 2011
Xcel Energy Inc. [Member]
Unsecured Senior Notes, Series Due Sept. 15, 2041 [Member]
May 31, 2010
Xcel Energy Inc. [Member]
Unsecured Senior Notes, Series Due May 15, 2020 [Member]
Dec. 31, 2011
Xcel Energy Inc. [Member]
Junior Subordinated Notes, Series Due Jan. 1, 2068 [Member]
Commercial Paper [Abstract]                                                            
Borrowing limit $ 2,450,000,000 $ 2,450,000,000 $ 2,177,000,000 $ 2,177,000,000                                                    
Amount outstanding at period end 219,000,000 219,000,000 466,400,000 459,000,000                                         127,000,000 148,000,000        
Average amount outstanding 165,000,000 430,000,000 263,000,000 406,000,000                                                    
Maximum amount outstanding 241,000,000 824,000,000 653,000,000 675,000,000                                                    
Weighted average interest rate, computed on a daily basis (in hundredths) 0.35% 0.36% 0.36% 0.95%                                                    
Weighted average interest rate at end of period (in hundredths) 0.40% 0.40% 0.40% 0.36%                                                    
Credit Facilities [Abstract]                                                            
Original term (in years)                   4Y       4Y         4Y       4Y   4Y          
Termination date                   2015-03       2015-03         2015-03       2015-03   2015-03          
Number of additional periods the revolving termination date can be extended, subject to majority bank group approval (in periods)                   2       2         2       2   2          
Term of each additional period the revolving termination date can be extended, subject to majority bank group approval (in years)                   1Y       1Y         1Y       1Y   1Y          
Maximum amount credit facility may be increased                   100,000,000       100,000,000         50,000,000           200,000,000          
Maximum debt-to-total capitalization ratio allowed (in hundredths) 65.00% 65.00%               65.00%       65.00%         65.00%       65.00%              
Debt-to-total capitalization ratio (in hundredths) 55.00% 55.00%               48.00%       45.00%         48.00%       50.00%              
Minimum threshold percentage of subsidiary assets to consolidated assets required to initiate cross default provisions (in hundredths)                                                 15.00%          
Minimum amount of indebtedness to initiate cross default provisions                                                 75,000,000          
Minimum borrowing margin based on current credit ratings (in hundredths)                   0.00%       0.00%         0.00%       0.00%   0.00%          
Maximum borrowing margin based on current credit ratings (in hundredths)                   2.00%       2.00%         2.00%       2.00%   2.00%          
Minimum commitment fees calculated on unused portion of lines of credit (in hundredths)                   0.10%       0.10%         0.10%       0.10%   0.10%          
Maximum commitment fees calculated on unused portion of lines of credit (in hundredths)                   0.35%       0.35%         0.35%       0.35%   0.35%          
Committed Credit Facilities [Abstract]                                                            
Credit facility 2,450,000,000 2,450,000,000               500,000,000       700,000,000         300,000,000       150,000,000   800,000,000          
Drawn 231,700,000 [1] 231,700,000 [1]               33,700,000 [1]       4,900,000 [1]         0 [1]       66,000,000 [1]   127,100,000 [1]          
Available 2,218,300,000 2,218,300,000               466,300,000       695,100,000         300,000,000       84,000,000   672,900,000          
Credit facility bank borrowings outstanding 0 0 0             0 0     0 0       0 0     0 0 0 0        
Letters of Credit [Abstract]                                                            
Terms of letters of credit (in years)   1Y                                                        
Letters of credit drawn under credit facilities 12,700,000 12,700,000 10,100,000                                                      
Letters of credit drawn outside of credit facilities 1,100,000 1,100,000 1,100,000                                                      
Dividend and Other Capital-Related Restrictions [Abstract]                                                            
Additional cash dividends on common stock which could have been paid per NSP-Minnesota's first mortgage indenture                   1,200,000,000 1,100,000,000                                      
Equity-to-total capitalization ratio, lower range (in hundredths)                   47.07%                                        
Equity-to-total capitalization ratio, higher range (in hundredths)                   57.53%                                        
Equity-to-total capitalization ratio, lower range (in hundredths)                                             52.50%              
Equity-to-total capitalization ratio, lower range (in hundredths)                                     45.00%                      
Equity-to-total capitalization ratio, higher range (in hundredths)                                     55.00%                      
Capitalization ratio (in hundredths)                   52.10%                 52.00%       55.10%              
Maximum total capitalization for NSP-Minnesota                   8,250,000,000                                        
Maximum long-term debt authorized for issuance                           1,150,000,000                 150,000,000              
Maximum short-term debt authorized for issuance                           800,000,000         400,000,000       150,000,000              
Maximum percentage of total capitalization short-term debt cannot exceed (in hundredths)                   15.00%                                        
Long Term Borrowings [Abstract]                                                            
Preferred stock, redemption purchase price         108,000,000                                                  
Debt instrument, gross amount                                                           400,000,000
Debt instrument, issuance date                       2010-08 2010-08       2011-08 2010-11       2011-08           2011-09 2010-05  
Debt instrument, issuer                       NSP-Minnesota NSP-Minnesota       PSCo PSCo       SPS           Xcel Energy Inc. Xcel Energy Inc. Xcel Energy Inc.
Debt instrument, face amount                       250,000,000 250,000,000       250,000,000 400,000,000       200,000,000           250,000,000 550,000,000  
Debt instrument, interest rate, stated percentage (in hundredths)                       1.95% 4.85%       4.75% 3.20%       4.50%           4.80% 4.70% 7.60%
Debt instrument, maturity date                       Aug. 15, 2015 Aug. 15, 2040       Aug. 15, 2041 Nov. 15, 2020       Aug. 15, 2041           Sep. 15, 2041 May 15, 2020 Jan. 01, 2068
Maximum number of days prior to the redemption or repurchase date when qualifying securities are issued to non-affiliates in a replacement offering (in days)                                                           180D
Maturities of Long-Term Debt [Abstract]                                                            
2012 1,060,000,000 1,060,000,000                                                        
2013 257,000,000 257,000,000                                                        
2014 282,000,000 282,000,000                                                        
2015 256,000,000 256,000,000                                                        
2016 207,000,000 207,000,000                                                        
Deferred Financing Costs [Abstract]                                                            
Deferred financing costs, net of amortization included in other assets 75,000,000 75,000,000 74,000,000                                                      
Capital Stock [Abstract]                                                            
Preferred stock, shares authorized (in shares) 7,000,000 7,000,000 7,000,000     7,000,000 7,000,000                 10,000,000         10,000,000                  
Preferred stock, par value (in dollars per share) $ 100 $ 100 $ 100     $ 100 $ 100                 $ 0.01         $ 1.00                  
Preferred stock, shares outstanding (in shares) 0 0 1,049,800     0 1,049,800                 0         0                  
Number of series of preferred stock outstanding             6                                              
Preferred stock, redeemable price, lower range (in dollars per share)             $ 102                                              
Preferred stock, redeemable price, higher range (in dollars per share)             $ 103.75                                              
Preferred stock, redemption premium   $ 3,260,000 $ 0 $ 0                                         $ 3,260,000 $ 0 $ 0      
Common stock, shares authorized (in shares) 1,000,000,000 1,000,000,000 1,000,000,000         1,000,000,000 1,000,000,000                                          
Common stock, shares outstanding (in shares) 486,493,933 486,493,933 482,333,750         486,493,933 482,333,750                                          
[1] Includes outstanding commercial paper and letters of credit.